This invention relates to a reinforced elastomeric lining for a pump casing. More particularly, this invention relates to a half-shell reinforced elastomer lining for a centrifugal pump casing. In addition, this invention relates to a method for manufacturing a pump lining.
Centrifugal pumps for moving slurries and corrosive liquids such as acids are generally protected on their inner surfaces with elastomer linings. To prevent collapse of a lining during use, particularly in a large centrifugal pump, the lining is occasionally bonded to the pump casing. U.S. Pat. No. 3,607,600 to Shreter discloses a bonding technique wherein the inner surface of the pump casing is provided with a coating of elastomer, then a layer of chopped fibers and several layers of synthetic resin material. The synthetic resin is rolled to mix the elastomer, the resin and the fibers.
A primary disadvantage of attaching a lining to a pump casing becomes obvious when the lining wears out and requires replacement. Frequently, the entire pump casing must be replaced.
U.S. Pat. No. 4,776,760 to Grisz discloses a centrifugal pump lining which is reinforced in selected areas with a resin impregnated fabric which permits the elastomer to shrink its normal amount during curing. In manufacturing such a pump lining, a mold is lined with thermosetting resin impregnated fabric in those regions where reinforcement is desirable. Once one or more fabric layers are in place, the uppermost fabric sheet is coated with a bonding material or adhesive for vulcanizing the elastomer to the fabric material. The elastomer is typical in the form of sheets which are deposited over the adhesive coating. The mold is subsequently closed and subjected to compression and heat for a predetermined period. The elastomer, adhesive and thermoset impregnated fabric are cured for a time and at a temperature sufficient to cure both the elastomer and the resin. During the curing process, the elastomer and the resin shrink to a similar extent.
Conventional rubber linings are difficult to match precisely to the inner surfaces of the casings into which the are placed. Because of shrinkage gradients, some warpage inevitably occurs during the curing process. Shrinkage problems escalate with increasing pump casing size and variation in elastomer type.